Reclosable packages are becoming a progressively larger part of the packaged food market because of increasing consumer preference. It is likely that eventually all packaged consumables will be marketed in reclosable packages. In the past, there have been attempts to devise such reclosable packages, but such previous attempts exhibit major shortcomings. One such previous approach is disclosed in European Patent EP 1254846 assigned to Amcor Flexibles. This patent discloses a structure in which a tearstrip is formed from a marginal edge of the packaging film along the package longitudinal seal, the tearstrip functioning to hold the package reclosed as shown in the patent drawings. No more than 20% of packaging films are suitable for utilizing the disclosed structure. Moreover, this structure will not work on a two roll system that fabricates a four-side-seal package as there is no longitudinal fin or lap seal packaging material from which to form the tearstrip which, as shown in the patent, must be coextensive with and attached to the longitudinal package seal. The reclosable package according to the present invention is not so limited.
Additionally, the Amcor structure uses double-faced adhesive tape or hot melt adhesive in combination with the strip of packaging film to secure the tearstrip to the package. The double-faced tape utilizes a silicone coated release liner which must be disposed of during production. This is both expensive and inconvenient. Additionally, because most of the package films, particularly those such as double polypropylene laminate used for packaging food products, have low tear resistance, the reclosure strip can tear instead of detaching from the package. This requires that the double-faced tape used must have different adhesives on the two faces, a strong adhesive bonding to the reclosure strip and a weak adhesive bonding to the package film. This is expensive tape. Moreover, as shown in FIG. 4 of the Amcor drawings, the double-faced tape is widthwise coextensive with the packaging film tearstrip and results in a package reclosing strip that is very difficult to separate from the package for use because there is no dry edge that can be grasped. Hot melt adhesive applied on-line is messy, has slow start-up, and is problematic and expensive. The novel reclosure strip and package according to the present invention suffer from none of the foregoing defects.
The difficulties with the foregoing described structure were apparently recognized, and a modified structure devised which is disclosed in Amcor published PCT patent application WO 2004/035389. While this modified structure utilizes a double-faced adhesive tape that is narrower than the tearstrip to provide a dry edge for grasping, it still utilizes a reclosure strip that is obtained by cutting the strip off of the marginal edge of the packaging material and applying it to a double-faced adhesive-coated tape, as in the Amcor European Patent EP 1254846. This has several disadvantages. First, it retains the same disadvantages with regard to the double-faced tape as the Amcor European Patent EP 1254846, as previously noted. Equally important, if the packaging manufacturer must provide the same SKU product in two package forms, one being a reclosable package and the other not, two separate packaging films must be inventoried because of the difference in packaging film width and graphics. This is a substantial expense to the manufacturer but is a not uncommon requirement, because some customers want the reclosable feature and some do not want to pay for the extra packaging cost. Further, extensible films are widely used for packaging, and stretching during formation will cause wrinkles and curves. Again, the novel reclosure strips and packages according to the present invention do not suffer from these defects.
Another known type of reclosable package utilizes a stick-on label as a package reclosing device. Such labels have a number of disadvantages that render them generally unsatisfactory. First, the labels generally are short relative to the package length, must be removed before use and reset on the package after the open package top has been rolled down, and when removed become contaminated with skin oils and product dust which destroys the adhesive qualities and allows the package to come open. Second, the labels are supplied on a release liner, which must be disposed of after the labels are detached for use. Additionally, label application is expensive, requiring two label applicators per packaging line to insure that every package has a label. Moreover, label application is not positionally precise, which may interfere with visually desirable graphics on the package. Over all, label application is not a very desirable system.
In my previous patent application, Ser. 1No. 11/120,953, entitled “Reclosable Packages,” I disclosed a two-part composite reclosable packaging strip as shown here in FIG. 1, wherein the film strip 48 is not itself adhered to the package 43 but is secured thereon by the single-faced tape 47 whose adhesive layer 49 adheres it to the package. The reclosing strip 41 is activated by grasping the film strip 48 and lifting or pivoting it outward. This permits grasping the reclosing strip 41 and pulling it downward to partially detach it from the package 43. A limitation of this construction is that printing applied to film strip 48 cannot extend the full width of the reclosing strip. This limitation is addressed in an alternate embodiment also disclosed in my previous patent application, shown herein in FIG. 2, which provides full-width graphics. As shown in FIG. 2, reclosing strip 31 consists of a film substrate 32 which may have graphics 33 printed thereon as shown. The strip is adhered to the packaging by a pressure sensitive adhesive layer 34. However, with this construction the graphics on the dry edge of the reclosing strip, that is the portion not covered by the adhesive 34 which attaches the strip to the package, are left unprotected and can wear off during use.